在十二指肠球部溃疡约占十二指肠溃疡的百分率是（）
A.50%
B.60%
C.70%
D.80%
E.90%
参考答案：E
In a documentary credit, terms such as “divisible”, “assignable”, and “transmissible” carry the same meaning and have the same effect as the term “transferable” and are interchangeably used with such a term.（）
利用微库仑仪测定样品时，测定成功与否的关键步骤是（）。
A.检查裂解炉
B.设定好温度
C.完成好滴定池操作
D.气流量调节
